某冶炼厂环境铅污染及其对人群健康影响的研究

目的　比较某冶炼厂环境铅污染 1 5年前后的变化 ,为该厂扩建投产后污染变化评价提供依据。方法　选取 1 980～ 1 982年调查时污染区中的厂南区和对照区 ,于 1 995～ 1 997年再次调查两区稻米、蔬菜、井水中的铅含量以及学龄儿童的血铅及δ-氨基乙酰丙酸脱水酶 (δ -ALAD)活力 ,并比较两次调查结果。结果　本次调查样品的几何均值米铅 (干重 )、菜铅 (湿重 )、井水铅、学生血铅和δ -ALAD酶活力 ,污染区分别为 2 6.7± 1 .65mg/kg、60 .4± 2 .67mg/kg、0 .0 1 4± 0 .0 0 5mg/L、2 0 6± 1 .7μg/L和 98± 1 .3IU/L ,对照区分别为 1 3 .2± 1 .85mg/kg、4 4.9± 2 .84mg/kg、0 .0 2 0± 0 .0 0 5mg/L、2 2 9± 1 .3 μg/L和 2 2 5± 1 .4IU/L。两区比较米铅含量污染区高于对照区 ,而酶活力前者明显低于后者 (P <0 .0 1 ) ;污染区有 2 2个学生 (占 2 1 .2 % )超过对照区学生血铅最高值 ( 3 1 2 .9μg/L) ,其中 8人的血铅值高达 4 50～ 762 μg/L。与 1 980～ 1 982年调查结果相比 ,污染区的稻米蔬菜铅含量显著增加。结论　该冶炼厂对污染区的铅污染有不断累积加重的趋势。     

多孔碳酸钙陶瓷细胞相容性评价

目的:探讨多孔碳酸钙陶瓷CCC的细胞相容性,为临床应用提供实验依据。方法:采用浸提法制备CCC生理盐水和培养液浸提液,浸提液体外培养L929小鼠成纤维细胞,进行细胞形态学观察,采用MTT法测定细胞增殖率并进行细胞毒性分级;采用分光光度法进行溶血试验。结果:培养期细胞大量增殖,形态良好,(CCC)的细胞毒性分级为Ⅰ级,对健康人血的溶血率<5%,存在轻微细胞毒性和溶血作用。结论:CCC细胞相容性好,符合植入人体生物材料的相关要求。     

Biologically Formed Amorphous Calcium Carbonate

Many organisms from a wide variety of taxa produce amorphous calcium carbonate (ACC), despite the fact that it is inherently unstable and relatively soluble in its pure state. These properties also make it difficult to detect and characterize ACC. Raman spectroscopy is a particularly useful method for investigating ACC because the sample can be examined wet, and extended X-ray absorption fine structure (EXAFS) analysis can provide detailed information on the short-range order. Other methods for characterizing ACC include infrared spectroscopy, thermogravimetric analysis and differential thermal analysis (TGA and DTA), transmission electron microscopy (TEM), and electron and X-ray diffraction. Because of the difficulties involved, we suspect that ACC is far more widely distributed than is presently known, and a comparison of EXAFS spectra shows that different biogenic ACC phases have different short-range order structures. We also suspect that ACC fulfils many different functions, including as a transient precursor phase during the formation of crystalline calcium carbonate.     

δ-aminolevulinate dehydratase activity in lung cancer patients and its relationship with oxidative stress

This study investigated the δ-aminolevulinate dehydratase (δ-ALA-D) activity in whole blood as well as the parameters of oxidative stress, such as reactive species (RS) levels in serum, thiobarbituric acid reactive substances (TBARS) levels, the superoxide dismutase (SOD) and catalase (CAT) activities, as well as total thiols (T-SH) and non-protein thiols (NPSH) levels in platelets. Moreover, the content of vitamin C and E in plasma and serum, respectively, in lung cancer patients was also investigated. We collected blood samples from patients (n = 28) previously treated for lung cancer with chemotherapy. Patients were classified as stage IIIb and IV according to the Union for International Cancer Control (UICC). Results showed a decrease of 37% in δ-ALA-D activity in patients with lung cancer when compared to the control group. RS and TBARS levels were 8% and 99% higher in the patient group, respectively. The activity of SOD and CAT as well as the vitamin C content were 41%, 35% and 127% lower in patients when compared with controls, respectively. However, T-SH and vitamin E levels were 27% and 44% higher in lung cancer patients, respectively. Results show that the overproduction of reactive species in patients with lung cancer may be interfering with the activity of δ-ALA-D. Likewise, the decrease in the activity of this enzyme may be contributing for the oxidative stress.     

Probing atomic scale transformation of fossil dental enamel using Fourier transform infrared and nuclear magnetic resonance spectroscopy: A case study from the Tugen Hills (Rift Gregory,Kenya)

A series of fossil tooth enamel samples was investigated by Fourier transform infrared (FTIR) spectroscopy, ¹³C and ¹⁹F magic-angle spinning nuclear magnetic resonance (MAS NMR) and scanning electron microscopy (SEM). Tooth remains were collected in Mio-Pliocene deposits of the Tugen Hills in Kenya. Significant transformations were observed in fossil enamel as a function of increasing fluorine content (up to 2.8 wt.%). FTIR spectroscopy revealed a shift of the ν₁ PO₄ stretching band to higher frequency. The ν₂ CO₃ vibrational band showed a decrease in the intensity of the primary B-type carbonate signal, which was replaced by a specific band at 864 cm⁻¹. This last band was ascribed to a specific carbonate environment in which the carbonate group is closely associated to a fluoride ion. The occurrence of this carbonate defect was consistently attested by the observation of two different fluoride signals in the ¹⁹F NMR spectra. One main signal, at ∼−100 ppm, is related to structural F ions in the apatite channel and the other, at −88 ppm, corresponds to the composite defect. These spectroscopic observations can be understood as resulting from the mixture of two phases: biogenic hydroxylapatite (bioapatite) and secondary fluorapatite. SEM observations of the most altered sample confirmed the extensive replacement of the bioapatite by fluorapatite, resulting from the dissolution of the primary bioapatite followed by the precipitation of carbonate-fluorapatite. The ν₂ CO₃ IR bands can be efficiently used to monitor the extent of this type of bioapatite transformation during fossilization.     

唑来膦酸注射液联合碳酸钙D3片治疗老年女性骨质疏松症的疗效观察

目的:探讨唑来膦酸注射液联合碳酸钙D3片治疗老年女性骨质疏松症的临床疗效。方法:以2013年1月至2018年5月赤峰市医院收治的老年女性骨质疏松症患者192例作为研究对象,采用随机数字表分为唑来膦酸组(给予唑来膦酸注射液治疗)、碳酸钙D3组(给予碳酸钙D3片治疗)及联合用药组(给予唑来膦酸注射液联合碳酸钙D3片治疗),每组64例。比较三组患者治疗前后血磷和血钙的含量、骨密度(包括Ward三角区、股骨大转子、股骨颈和腰椎L2—4骨密度)、骨代谢相关生化指标[骨特异性碱性磷酸酶(BAP)、骨钙素(BGP)、人抗酒石酸酸性磷酸酶5b(TRAP-5b)和Ⅰ型胶原羟基端肽β降解产物(β-CTX)]含量及临床疗效的差异。结果:随着时间迁移,三组患者血磷、血钙、BAP及BGP含量,股骨大转子、股骨颈及腰椎L2—4骨密度呈显著升高趋势;而TRAP-5b、β-CTX含量呈显著降低趋势。治疗后,三组患者血磷、血钙、BAP、BGP、TRAP-5b及β-CTX含量,股骨大转子、股骨颈及腰椎L2—4骨密度的差异均有统计学意义(P<0.05)。治疗后,联合组患者血磷、血钙、BAP及BGP含量,股骨大转子、股骨颈及腰椎L2—4骨密度明显高于唑来膦酸组和碳酸钙D3组,TRAP-5b含量明显低于唑来膦酸组和碳酸钙D3组,差异均有统计学意义(P<0.05)。联合组患者的总有效率为92.19%(59/64),明显优于唑来膦酸组的79.69%(51/64)和碳酸钙D3组的78.13%(50/64),差异均有统计学意义(P<0.05)。结论:唑来膦酸注射液和碳酸钙D3片对老年女性骨质疏松症有一定的疗效,二者联合治疗的效果更好。     

Hereditary hepatic porphyria due to homozygous δ-aminolevulinic acid dehydratase deficiency: studies in lymphocytes and erythrocytes

Activities of delta-aminolevulinic acid (ALA) dehydratase and porphobilinogen (PBG) deaminase, and haem content were determined in EB-virus transformed lymphocytes from two patients with homozygous ALA dehydratase deficiency, and their family members to determine the expression of the specific gene defect in this cell type. ALA dehydratase activity, but not PBG deaminase activity or haem content, was markedly decreased in lymphocyte preparations from both patients with homozygous enzyme deficiency, and moderately decreased in subjects heterozygous for enzyme deficiency. Immunochemical quantitation of erythrocyte ALA dehydratase suggested the presence of a cross-reactive material in a patient with a late-onset of acute hepatic porphyria due to the homozygous enzyme deficiency.     

Infrared determination of the degree of substitution of hydroxyl by carbonate ions in human dental enamel

Summary About 11±1% of the carbonate ions in a human tooth enamel specimen (dense fraction, sp. g.>2.95) were found to be in the A-sites, replacing hydroxyl ions. The determination was made with a difference infrared spectrometry technique utilizing both tooth enamel and a reconstituted biological apatite with a known amount of replacement of hydroxyl by carbonate ions.     

ROLE OF ZINC IN ENZYME REGULATION AND PROTECTION OF ESSENTIAL THIOL GROUPS

Zinc protects essential thiol groups from air oxidation in some enzymes and also plays a key role at active sites of classic zinc metalloenzymes.     

ESR study of 13C-enriched carbonated calciumapatites precipitated from aqueous solutions

Summary The ESR spectrum of X-irradiated carbonated apatites precipitated from aqueous solutions was studied at carbonate contents ranging from approximately 5.4 up to 12.4 wt%. ¹²C- as well as ¹³C-enriched samples were prepared and examined with ESR after drying until constant weight at 25°C and 400°C. In these carbonated apatites, two CO₃ ^3- radicals were detected, one of which is derived from B-type carbonate situated at a phosphate lattice site. The other CO₃ ^3- most probably arises from CO₃ ^2- ions situated at OH^- lattice sites. In contradistinction to the B-type contribution, the A-type contribution to the overall ESR signal decreases in absolute terms with increasing carbonate concentration. In addition, the line shape and the complete set of principal g-values of the A1-signal found in previous studles could be determined, corroborating the assignment of A1 to a surface O^- ion.Research Associate of the N.F.S.R. (Belgium)